Trisubstituted benzoic acid intermediates

ABSTRACT

Novel trisubstituted benzoic acid intermediates which are useful in the preparation of certain herbicidal 2-(2,3,4-trisubstituted benzoyl)-1,3-cyclohexanediones are described.

This is a divisional of application Ser. No. 07/386,648 filed July 31,1989, now U.S. Pat. No. 5,001,256 which is a divisional of applicationSer. No. 07/273,391, filed Nov. 18, 1988, now abandoned.

BACKGROUND OF THE INVENTION

Certain 2-(2'3'4'tri-substituted benzoyl)-1,3-cyclohexanedioneherbicides are described in U.S. Pat. No. 4,780,127, issued Oct. 25,1988, U.S. application Ser. No. 129,026, filed Dec. 4, 1987; and a U.S.application entitled 2-(2',3',4'-trisubstitutedbenzoyl)-1,3-cyclohexanediones, with William J. Michaely, inventor,filed herewith, and all incorporated herein by reference.

The above-described herbicidal compounds can have the followingstructural formula ##STR1## wherein R⁷ through R¹² are hydrogen or C₁-C₄ alkyl; R¹ is C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, CH₂ CH₂ --OCH₃, CH₂ CH₂OC₂ H₅, CH₂ CH₂ SCH₃, or CH₂ CH₂ SC₂ H₅ ; R² is C₁ -C₄ alkyl; and n isthe integer 0 or 2.

These herbicides can be prepared by reacting a dione of the structuralformula ##STR2## wherein R⁷ through R¹² are as defined with a mole oftrisubstituted benzoyl chloride of the structural formula ##STR3##wherein n, R¹ and R² are as defined above.

DESCRIPTION OF THE INVENTION

This invention has several embodiments which are as follows:

Embodiment A relates to novel intermediate compounds having thestructural formula ##STR4## wherein R is cyano; carboxy; or --CO₂ R_(a)where R_(a) is C₁ -C₄ alkyl, preferably ethyl; most preferably R is--CO₂ C₂ H₅.

Embodiment B relates to novel intermediate compounds having thestructural formula ##STR5## wherein R is cyano; carboxy or --CO₂ R_(a)wherein R_(a) is C₁ -C₄ alkyl, preferably ethyl, most preferably R is--CO₂ C₂ H₅ and R¹ is C₁ -C₄ alkyl; preferably C₁ -C₂ alkyl; C₁ -C₄haloalkyl; --CH₂ CH₂ OCH₃ ; --CH₂ CH₂ OC₂ H₅ ; --CH₂ CH₂ SCH₃ or --CH₂CH₂ SC₂ H₅, with the proviso that when R is carboxy, then R¹ is --CH₂CH₂ OCH₃ ; --CH₂ CH₂ OC₂ H₅ ; --CH₂ CH₂ SCH₃ or --CH₂ CH₂ SC₂ H₅.

Embodiment C relates to novel intermediate compounds having thestructural formula ##STR6## wherein R is cyano; carboxy or --CO₂ R_(a)wherein R_(a) is C₁ -C₄ alkyl, preferably ethyl, most preferably R isCO₂ C₂ H₅ ; R¹ is C₁ -C₄ alkyl; C₁ -C₄ haloalkyl; --CH₂ CH₂ OCH₃, --CH₂CH₂ OC₂ H₅, --CH₂ CH₂ SCH₃ or --CH₂ CH₂ SC₂ H₅ and R² is C₁ -C₄ alkyl,preferably methyl, ethyl or n-propyl with the proviso that when R iscarboxy, then R¹ is --CH₂ CH₂ OCH₃, --CH₂ CH₂ OC₂ H₅, --CH₂ CH₂ SCH₃ or--CH₂ CH₂ SC₂ H₅.

Embodiment D relates to novel intermediate compounds having thestructural formula ##STR7## wherein X is chlorine or hydroxy; R⁴ is--CH₂ CH₂ OCH₃, --CH₂ CH₂ OC₂ H₅, --CH₂ CH₂ SCH₃ or --CH₂ CH₂ SC₂ H₅,preferably --CH₂ CH₂ OCH₃ or --CH₂ CH₂ OC₂ H₅ ; and R² is C₁ -C₄ alkyl,preferably methyl, ethyl or n-propyl.

Embodiment E relates to novel intermediate compounds having thestructural formula ##STR8## wherein X is hydroxy or chlorine; R³ is--CH₂ CH₂ OCH₃ or --CH₂ CH₂ OC₂ H₅ and R² is C₁ -C₄ alkyl, preferablymethyl, ethyl or n-propyl.

Embodiment F relates to novel intermediate compounds having thestructural formula ##STR9## wherein R^(a) is C₁ -C₄ alkyl, preferablyethyl, R⁵ is C₁ -C₄ alkyl; C₁ -C₄ haloalkyl; --CH₂ CH₂ OCH₃ or --CH₂ CH₂OC₂ H₅ ; preferably --CH₂ CH₂ OCH₃ or --CH₂ CH₂ OC₂ H₅ and R² is C₁ -C₄alkyl, preferably methyl, ethyl or n-propyl.

In embodiments A-C, the group R can also be trifluoromethyl.

The several intermediate compounds of this invention can be prepared bythe general method shown in the Figure of the next page with R, R¹, R²and R⁵ being as defined. The group R^(z) is C₁ -C₄ alkyl. ##STR10##

Referring to the Figure, and particularly to Reaction Steps (A) through(G), consider the following:

Generally in Reaction Step (A), a mole amount of the 3-substitutedphenol is reacted with 2 moles of chlorine and a catalytic amount of aC₁ -C₁₀ alkylamine, preferably tert-butylamine or diisopropylamine in asolvent such as methylene chloride, at a temperature between -70° C. to70° C. After this reaction, the free chlorinated phenol is isolated bynormal procedures.

For Reaction Step (B), one mole of the dichloro-substituted phenolreaction product of Step (A) is reacted with an appropriate alkylatingagent such as a 2-chloroethyl ethyl ether, 2-chloroethyl methyl ether,2-chloroethyl methyl sulfide, 2-chloroethyl ethyl sulfide or C₁ -C₄alkylchloride along with a catalytic amount of potassium iodide and amole excess of a base such as potassium carbonate. Alkyl iodides such asmethyl iodide or ethyl iodide may also be used. In these cases thecatalytic potassium iodide is not needed and little or no heat isrequired. The reaction is run at 25° C. to 80° C. for 4 hours withagitation. The reaction product is recovered by conventional techniques.

For Reaction Step (C), the dichloro compound from Reaction Step (B) isreacted with an equal mole amount of a C₁ -C₄ alkyl mercaptan along witha mole excess of a base such as potassium carbonate in a solvent such asdimethylformamide. The reaction is run for several hours at atemperature between 50° C. to 100° C. with stirring under an inertatmosphere such as nitrogen. The desired reaction product is recoveredby conventional techniques.

For Reaction Step (D) a mole amount of the alkyl ester of2-chloro-4-alkylthio benzoic compound is oxidized with at least 3 molesof an oxidizing agent such as m-chloroperbenzoic acid in a suitablesolvent such as methylene chloride by stirring a solution of thereactants at 20° to 100° C. The desired intermediate is recovered byconventional techniques. During this reaction step the 4-alkylthiosubstituent is oxidized to the corresponding alkylsulfone.

For Reaction Step (E) a mole amount of the2-chloro-3-substituted-4-alkylthio ester or cyano compound is hydrolyzedwith a base such as sodium hydroxide to the corresponding2-chloro-3-substituted-4-alkylthio benzoic acid. The hydrolysis is runin a solvent such as an 80 percent methanol-water mixture. The reactioncan be run at 25°-100° C. with stirring. The desired product isrecovered by conventional techniques.

For Reaction Step (F) the alkyl ester of the trisubstituted benzoic acidis converted to the trisubstituted benzoic acid by the hydrolysis steptaught in Reaction Step (E)

In the alternative, the tri-substituted benzoic acid reaction product ofReaction Step (F) can be directly prepared from the reaction product ofReaction Step (C) by a combination hydrolysis of the2-chloro-3-substituted-4-alkylthio ester or cyano compound to thecorresponding benzoic acid and an oxidation of the 4-alkylthiosubstituent to the corresponding 4-alkylsulfone. The hydrolysis andoxidation steps can be jointly carried out by reacting a mole of theester or cyano compound with at least 5 moles of sodium or calciumhypochlorite in a suitable solvent such as dioxane-water, by heating asolution of the reactants from about 25° C. to about 100° C., followedby the acidification with concentrated hydrochloric acid. Filtration ofthe resulting precipitate yields the desired product.

For Reaction Step (G) the dichloro compound from Reaction Step (B) isconverted to the benzoic acid by the hydrolysis step taught in ReactionStep (E).

The intermediate benzoic acids described herein can easily be convertedto their respective acid chlorides and then to their acid cyanides, ifdesired, by the following two reactions. First, a mole of oxalylchloride and a catalytic amount of dimethylformamide in a suitablesolvent such as methylene chloride at a temperature of 20° to 40° C. for1 to 4 hours is heated with a mole of the intermediate benzoic acid. Thecorresponding benzoic acid cyanide can easily be prepared from thebenzoic acid chloride by reaction with cuprous cyanide at a temperatureof 50° to 220° C. for 1 to 2 hours.

The trisubstituted benzoic acid chloride intermediates are useful in thepreparation of the previously described herbicidal2-(2',3',4'-trisubstituted benzoyl)-1,3-cyclohexanediones.

The following series of examples teach the synthesis of representativeintermediate compounds of this invention. The structures of allcompounds of the examples and tables were verified by nuclear magneticresonance (NMR), infrared spectroscopy (IR) and mass spectroscopy (MS).

EXAMPLE 1 Ethyl 2,4-chloro-3-hydroxybenzoate ##STR11##

In a 3-neck, 1-liter flask equipped with a mechanical stirrer,condenser, thermometer and a diffusion tube was added a solution of 106grams (0.64 mole) ethyl 3-hydroxybenzoate and 0.5 grams diisopropylaminein 600 milliliters (ml) dichloroethane at reflux. Chlorine (112 grams,1.6 mole) was added through the diffusion tube over a period of 6 hoursthen let cool to room temperature. After cooling, the solution waswashed with 200 ml 5% sodium bisulfite solution, then with 200 ml water,dried (MgSO₄) and reduced under vacuum. Yield was 151 g of an oil. Thismixture of chlorinated compounds (66% above product) can berecrystallized in ether/pentane by cooling to -20° C. to give pure ethyl2,4-dichloro-3-hydroxybenzoate. The structure of this compound and allexamples were verified by nuclear magnetic resonance (NMR), infraredspectroscopy (IR) and mass spectroscopy (MS).

Additional compounds were prepared by the same procedure as described inExample 1 and are listed in Table 1.

                  TABLE 1                                                         ______________________________________                                         ##STR12##                                                                    R               Yield (%) m.p. °C.                                     ______________________________________                                        CO.sub.2 CH.sub.3                                                                             72        57-64                                               CO.sub.2 CH(CH.sub.3).sub.2                                                                   66        oil                                                 ______________________________________                                    

EXAMPLE 2 Ethyl 2,4-chloro-3-(2-methoxyethoxy) benzoate ##STR13##

A solution of 18 g (77 millimoles, mmol) ethyl2,4-dichloro-3-hydroxybenzoate, 22 g (3 equivalents) (eq) 2-chloroethylmethyl ether, 22 g (2 eq) potassium carbonate and ca. 0.5 g sodiumiodide in 100 ml DMF was heated at 80° C. for 1.5 hours. To the cooledsolution was added 400 ml ether. The organic phase was washed with 100ml water (2 times), 100 ml 100% NaOH and 100 ml 10% HCl. Dried (MgSO₄)and reduced under vacuum. The yield was 20 g (68 mmole).

Additional compounds were prepared by the same procedure as described inExample 2 (except in those cases using alkyl iodide then the potassiumiodide catalyst was omitted and little or no heat is required) and arelisted in Table 2.

                  TABLE 2                                                         ______________________________________                                         ##STR14##                                                                                            Physical                                              R         R.sup.1       Property  Yield (%)                                   ______________________________________                                        CO.sub.2 C.sub.2 H.sub.5                                                                C.sub.2 H.sub.5                                                                             oil       92                                          CO.sub.2 C.sub.2 H.sub.5                                                                n-C.sub.3 H.sub.7                                                                           oil       100                                         CO.sub.2 C.sub.2 H.sub.5                                                                CH.sub.2 CH.sub.2 OCH.sub.3                                                                 oil       30                                          CO.sub.2 C.sub.2 H.sub.5                                                                CH.sub.2 CH.sub.2 Br                                                                        oil       95                                          CO.sub.2 C.sub.2 H.sub.5                                                                CH.sub.2 CH.sub.2 SCH.sub.2 H.sub.5                                                         oil       66                                          CO.sub.2 C.sub.2 H.sub.5                                                                CH.sub.2 CH.sub.2 Cl                                                                        oil       10                                          CO.sub.2 CH.sub.3                                                                       CH.sub.2 CF.sub.3                                                                           solid     57                                          ______________________________________                                    

EXAMPLE 3 Ethyl 2-chloro-3-(2-methoxyethoxy)-4-ethylthiobenzoate##STR15##

A solution of 10 g (34 mmole) ethyl2,4-dichloro-3-(2-methoxyethoxy)benzoate, 10 g (4 eq) ethanethiol and 10g (2 eq) potassium carbonate in 100 ml DMF was heated (approximately100° C.) for 2 hours, then let cool overnight. Added 400 ml diethylether and washed with 100 ml water (two times), 100 ml 10% HCl and 100ml 10% NaOH. Dried (MgSO₄) and reduced under vacuum. Yield 10 g (31mmole) of an oil.

Additional compounds were prepared by the same procedure as described inExample 3 and are listed in Table 3.

                  TABLE 3                                                         ______________________________________                                         ##STR16##                                                                    R          R.sup.1      R.sup.2 Yield (%)                                     ______________________________________                                        CO.sub.2 C.sub.2 H.sub.5                                                                 C.sub.2 H.sub.5                                                                            C.sub.2 H.sub.5                                                                       64                                            CO.sub.2 C.sub.2 H.sub.5                                                                 n-C.sub.3 H.sub.7                                                                          CH.sub.3                                                                              41                                            CO.sub.2 C.sub.2 H.sub.5                                                                 CH.sub.2 CH.sub.2 OCH.sub.3                                                                C.sub.2 H.sub.5                                                                       46                                            CO.sub.2 C.sub.2 H.sub.5                                                                 CH.sub.2 CH.sub.2 OCH.sub.3                                                                n-C.sub.3 H.sub.7                                                                     86                                            CO.sub.2 C.sub.2 H.sub.5                                                                 H            C.sub.2 H.sub.5                                                                       15                                            CO.sub.2 CH.sub.3                                                                        H            C.sub.2 H.sub.5                                                                       --                                            CO.sub.2 CH.sub.3                                                                        CH.sub.2 CH.sub.2 OCH.sub.3                                                                C.sub.2 H.sub.5                                                                       90                                            CO.sub.2 CH.sub.3                                                                        CH.sub.2 CH.sub.2 OCH.sub.3                                                                n-C.sub.3 H.sub.7                                                                     87                                            CO.sub.2 CH.sub.3                                                                        CH.sub.2 CH.sub.2 OCH.sub.3                                                                CH.sub.3                                                                              65                                            CO.sub.2 CH.sub.3                                                                        CH.sub.2 CF.sub.3                                                                          C.sub.2 H.sub.5                                                                       53                                            ______________________________________                                    

EXAMPLE 4 Ethyl 2-chloro-3-(2-methoxyethoxy)-4-ethylsulfonyl benzoate##STR17##

The ester, ethyl 2-chloro-3-(2-methoxyethoxy)-4-ethylthiobenzoate fromExample 3 (10 g) was dissolved in 100 ml of methylene chloride andcooled with an ice bath. Next 18 g solid m-chloroperoxybenzoic acid (85%pure, 2.2 equivalents) was added in portions over a period of 2 hours.The crude reaction mixture was allowed to warm to room temperature.After 1 hour at room temperature the excess peracid was destroyed withsodium bisulfite (100 ml 5% solution). The organic layer was washed twotimes with 5% sodium hydroxide (100%) and stripped under vacuum to give11.3 grams of pure ethyl2-chloro-3-(2-methoxyethoxy)-4-ethylsulfonylbenzoate as a viscous oil.

Additional compounds were prepared by the same procedure as described inExample 4 and are listed in Table 4.

                  TABLE 4                                                         ______________________________________                                         ##STR18##                                                                    R.sup.a  R.sup.5       R.sup.2 Yield (%)                                      ______________________________________                                        C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.5                                                                             C.sub.2 H.sub.5                                                                       90                                             C.sub.2 H.sub.5                                                                         -n-C.sub.3 H.sub.7                                                                         CH.sub.3                                                                              64                                             C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.4 OCH.sub.3                                                                   C.sub.2 H.sub.5                                                                       72                                             C.sub.2 H.sub.5                                                                        C.sub.2 H.sub.4 OCH.sub.3                                                                   n-C.sub.3 H.sub.7                                                                     98                                             CH.sub.3 CH.sub.2 CH.sub.2 Cl                                                                        n-C.sub.3 H.sub.7                                                                     --                                             CH.sub.3 C.sub.2 H.sub.4 OCH.sub.3                                                                   C.sub.2 H.sub.5                                                                       100                                            CH.sub.3 C.sub.2 H.sub.4 OCH.sub.3                                                                   n-C.sub.3 H.sub.7                                                                     97                                             CH.sub.3 CH.sub.2 CH.sub.2 OCH.sub.3                                                                 CH.sub.3                                                                              87                                             CH.sub.3 CH.sub.2 CF.sub.3                                                                           CH.sub.3                                                                              --                                             ______________________________________                                    

EXAMPLE 5 2-chloro-3-(2-methoxyethoxy)-4-ethylsulfonylbenzoic acid##STR19##

To 11.3 g (0.03 mole) of the ethyl2-chloro-3-(2-methoxyethoxy)-4-ethylsulfonylbenzoate in 100 ml of 96%ethanol was added dropwise 16 ml (1.2 eq) of 10% sodium hydroxide. Afterstirring at room temperature for 4 hours, 100 ml of diethyl ether wasadded and the organic phase was extracted with 50 ml of 5% NaOH. Theaqueous phase was acidified with 10% HCl and extracted two times with 50ml chloroform. The organic phase was dried with MgSO4 and concentratedunder vacuum to yield 8.8 grams of2-chloro-3-(2-methoxyethoxy)4-ethylsulfonylbenzoic acid as a viscousoil.

Additional compounds were prepared by the same procedure as described inExample 5 and are listed in Table 5.

                  TABLE 5                                                         ______________________________________                                         ##STR20##                                                                    R.sup.5          R.sup.2 Yield (%)                                            ______________________________________                                        CH.sub.2 CH.sub.2 OCH.sub.3                                                                    n-C.sub.3 H.sub.7                                                                     77                                                   CH.sub.2 CH.sub.2 OCH.sub.3                                                                    CH.sub.3                                                                              80                                                   ______________________________________                                    

EXAMPLE 6 2-Chloro-3-(2-methoxyethoxy)-4-ethylthio benzoic acid##STR21##

Three grams (8.2 mmol) ethyl2-chloro-3-(2-methoxyethoxy)-4-propanethiobenzoate was dissolved in 20ml 96% ethyl alcohol. To this was added 3.9 ml 10% sodium hydroxide inwater. After stirring 4 hours at room temperature, 100 ml of diethylether was added to the solution. The solution was extracted twice with50 ml 5% sodium hydroxide solution. The combined caustic extracts wereacidified with 10% hydrochloric acid and extracted twice with 50 mlportions of chloroform. The chloroform extracts were dried overmagnesium sulfate and the chloroform removed in vacuo to afford the freeacid (2.0 g, 72%) as a soft solid.

Additional compounds were prepared by the same procedure as described inExample 6 and are listed in Table 6.

                  TABLE 6                                                         ______________________________________                                         ##STR22##                                                                    R.sup.1          R.sup.2                                                                              Yield (%)                                             ______________________________________                                        CH.sub.2 CH.sub.2 OCH.sub.3                                                                    C.sub.2 H.sub.5                                                                      72                                                    ______________________________________                                    

EXAMPLE 7 2,4-Dichloro-3-(2-methoxyethoxy) benzoic acid ##STR23##

Sixteen grams (41 mmol) ethyl 2,4-dichloro-3-(2-methoxyethoxy)benzoatewas dissolved in 100 ml of 96% ethanol. To this was added, in portions,18 ml (ca 1.1 equivalents) 10% sodium hydroxide. After stirring 4 hoursat room temperature, 250 ml diethyl ether was added to the solution. Thesolution was extracted twice with 50 ml 5% sodium hydroxide. Thecombined caustic extracts were acidified with a 10% hydrochloric acidsolution and extracted twice with 75 ml portions of chloroform. Thechloroform extracts were dried (magnesium sulfate) and the chloroformremoved in vacuo to afford the free acid (12.8 g, 79%) as a white solid.

Additional compounds were prepared by the same procedure as described inExample 7 and are listed in Table 7.

                  TABLE 7                                                         ______________________________________                                         ##STR24##                                                                    R.sup.1         Yield (%)                                                     ______________________________________                                        CH.sub.2 CH.sub.2 SC.sub.2 H.sub.5                                                            100                                                           ______________________________________                                    

The above-described benzoic acids can be readily converted to their acidchlorides using oxalyl chloride and a catalytic amount ofdimethylformamide. These acid chlorides can be reacted with theabovedescribed 1,3-cyclohexanedione to prepare the above-describedherbicidal 2,3,4-trisubstituted benzoyl-1,3-cyclohexanediones accordingto the following two-step reaction:

The process proceeds via the production of an enol ester intermediate asshown in reaction (1). The final product is obtained by rearrangement ofthe enol ester as shown in reaction (2). The two reactions may beconducted as separate steps by isolation and recovery of the enol esterusing conventional techniques prior to conducting step (2), or byaddition of a cyanide source to the reaction medium after the formationof the enol ester, or in one step by inclusion of the cyanide source atthe start of reaction (1). ##STR25## wherein n and R¹, R² and R⁷ throughR¹² are as defined above and the moderate base is such as tri-C₁ -C₆alkylamine, pyridine, alkali metal carbonate or alkali metal phosphate.

Generally, in step (1) mole amounts of the dione and substituted benzoylchloride are used, along with a slight mole excess of a moderate base.The two reactants are combined in an organic solvent such asacetonitrile, methylene chloride, toluene, ethyl acetate ordimethylformamide. The base and benzoyl reactant preferably are added tothe reaction mixture with cooling. The mixture is stirred at 0° C.-50°C. until the reaction is substantially complete.

The reaction product is worked up by conventional techniques. ##STR26##wherein R¹, R² and R⁷ through R¹² are as defined above.

Generally, in step (2) a mole of the enol ester intermediate is reactedwith 1 to 4 moles of the base, preferably about 2 moles of moderate baseand from 0.01 mole to about 0.5 mole or higher, preferably around 0.1mole of the cyanide source (e.g., potassium cyanide or acetonecyanohydrin). The mixture is stirred in a reaction pot until therearrangement is substantially complete at a temperature below 80° C.,preferably about 20° C. to about 40° C., and the desired product isrecovered by conventional techniques.

The term "cyanide source" refers to a substance or substances whichunder the rearrangement conditions consists of or generates hydrogencyanide and/or cyanide anion.

The process is conducted in the presence of a catalytic amount of asource of cyanide anion and/or hydrogen cyanide, together with a molarexcess, with respect to the enol ester, of a moderate base.

Preferred cyanide sources are alkali metal cyanides such as sodium andpotassium cyanide; cyanohydrins of methyl alkyl ketones having from 1-4carbon atoms in the alkyl groups, such as acetone or methyl isobutylketone cyanohydrins; cyanohydrins of benzaldehyde or of C₂ -C₅ aliphaticaldehydes such as acetaldehyde, propionaldehyde, etc., cyanohydrins;zinc cyanide; and hydrogen cyanide itself. Hydrogen cyanide isconsidered most advantageous as it produces relatively rapid reactionand is inexpensive. Among cyanohydrins the preferred cyanide source isacetone cyanohydrin.

The cyanide source is used in an amount up to about 50 mole % based onthe enol ester. It may be used in as little as about 1 mole % to producean acceptable rate of reaction at about 40° C. on a small scale. Largerscale reactions give more reproducible results with slightly highercatalyst levels of about 2 mole %. Generally about 1-10 mole % of thecyanide source is preferred.

The process is conducted with a molar excess, with respect to the enolester, of a moderate base. By the term "moderate base" is meant asubstance which acts as a base yet whose strength or activity as a baselies between that of strong bases such as hydroxides (which could causehydrolysis of the enol ester) and that of weak bases such asbicarbonates (which would not function effectively). Moderate basessuitable for use in this embodiment include both organic bases such astertiary amines and inorganic bases such as alkali metal carbonates andphosphates. Suitable tertiary amines include trialkylamines such astriethylamine, trialkanolamines such as triethanolamine, and pyridine.Suitable inorganic bases include potassium carbonate and trisodiumphosphate.

The base is used in an amount of from about 1 to about 4 moles per moleof enol ester, preferably about 2 moles per mole.

When the cyanide source is an alkali metal cyanide, particularlypotassium cyanide, a phase transfer catalyst may be included in thereaction. Particularly suitable phase transfer catalysts are the Crownethers.

A number of different solvents may be usable in this process, dependingon the nature of the acid chloride or the acylated product. A preferredsolvent for this reaction is 1,2-dichloroethane. Other solvents whichmay be employed depending on the reactants or products include toluene,acetonitrile, methylene chloride, ethyl acetate, dimethylformamide, andmethyl isobutyl ketone (MIBK).

In general, depending on the nature of the reactants and the cyanidesource, the rearrangement may be conducted at temperatures up to about50° C.

What is claimed is:
 1. The compound of the structural formula ##STR27##wherein R⁴ is --CH₂ CH₂ OCH₃, --CH₂ CH₂ OC₂ H₅, --CH₂ CH₂ SCH₃ or --CH₂CH₂ SC₂ H₅ and R² is C₁ -C₄ alkyl.
 2. The compound of claim 1 wherein R⁴is --CH₂ CH₂ OCH₃ and R² is C₁ -C₄ alkyl.